<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <script src="./vue.js"></script>
    <style>
    </style>
</head>

<body>
    <div id="app">
        <p :style="{opacity:num}"> vue+_==_+_+_+_+_+_+_+_+_</p>
        <button @click="$destroy()"> 点击卸载 </button>
    </div>
    <script>
        Vue.config.productionTip = false;
        const vm = new Vue({
            el: "#app",
            data() {
                return {
                    num: 1,
                    interval: null
                };
            },
            mounted() {
                this.interval = setInterval(() => {
                    this.num -= 0.1
                    console.log(1);
                    if (this.num < 0) {
                        this.num = 1
                    }
                }, 100)
            },
            beforeDestroy() {
                clearInterval(this.interval)
            },
        });
    </script>
</body>

</html>